- fixed upgrade for po

sql/postgresql/upgrade/upgrade-5.5.0d3-5.5.0d4.sql

-alter table cr_revisions
-drop constraint cr_revisions_lob_fk;
+
+
+
+
+-- Drop contstraints if exists
+create or replace function inline_0 ()
+returns integer as '
+DECLARE
+	v_count                 integer;
+BEGIN
+	select count(*) into v_count from pg_constraint
+	where  lower(conname) = ''cr_revisions_lob_fk'';
+        IF v_count = 0 THEN return 0; END IF;
+
+	alter table cr_revisions
+	drop constraint cr_revisions_lob_fk;
+
+        return 0;
+end;' language 'plpgsql';
+select inline_0();
+drop function inline_0();
+
 
 alter table cr_revisions
 add constraint cr_revisions_lob_fk